1. Field of the Invention
The present invention relates to a filler tube, and a manufacturing process for the same.
2. Description of the Related Art
Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2014-231286 sets forth to weld the end face of a thermoplastic-resin filler tube to the opening of a fuel tank made of resin. The filler tube comprises a flange at the end to be welded to the fuel tank. Moreover, Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2003-194280 also sets forth to weld the end face of a filler tube to the opening of a fuel tank. A welding site in the filler tube is formed in a heavy thickness, compared with the other sites. Moreover, it is deemed possible to make the filler tube have a heavy thickness by corrugation molding.
Japanese Patent Gazette No. 5243904 sets forth to use high-density polyethylene resin (or HDPE) in order to enhance weldability in a joining part to be welded to a fuel tank made of resin. In addition, it sets forth not to use conventional ethylene-vinyl alcohol (or EVOH) copolymers for the joining part, but to use a special material including HDPE, in order to acquire fuel-permeation resistance property therefor. Thus, it is deemed possible to make the joining part satisfactory in the fuel-permeation resistance property and weldability.
Moreover, Japanese Patent Gazette No. 3575754 sets forth a structure applied to tubes and tanks, or the like, and comprising a first layer made of HDPE, a second layer made of EVOH as the major constituent, and a third layer made of polyamide or a mixture of polyamide and polyolefin.
In addition, Japanese Unexamined Patent Publication (KOKAI) Gazette No. 2015-55261 sets forth a manufacturing process for filler tube made of resin. According to the manufacturing process, corrugation molding is carried out to mold a tube comprising a bellows, and a non-bellows cylindrical base. In the corrugation molding, a cylindrical raw workpiece, which has been extruded by an extruder, is pressed by a corrugated mold against a cavity in the mold. Moreover, the non-bellows cylindrical base is subjected to bending forming by press processing.